You are right you can use the BufferedReader class for reading the big files which many range in many GB's is size.
It's not possible to read the whole file in memory. So, it's better to use the BufferedReader class.
The BufferedReader is present in java.io package. You can import
in your program and use the class for reading the file line by line.
You can use the
readLine() method of the class to read one line at a time very efficiently.
View the detailed example and code at Java Read File Line by Line - Java Tutorial page.